Self-assemblies of block copolymers lead typically only to local microphase separated structures with no overall alignment. To allow overall alignment of the polymeric self-assemblies, external fields can additionally be used, such as electric field, magnetic field, or flow. In films, substrate templating and graphoepitaxy have been applied. Aligning polymeric nanostructures up to macroscale in facile ways remains a challenge in materials science and technology. Here we show a supramolecular concept for polymeric self-assemblies where the nanoscale organization guides the macroscopic alignment from nanometers to millimeter-scale. The concept is shown by halogen bonding (Cavallo et al, Chem. Soc. Rev. 2010, 39, 3772) mesogenic 1-iodoperfluoroalkanes to a star-shaped ethyleneglycol-based polymer, having ammonium chloride end-groups. The star-shape architecture was expected to suppress entanglements. The mesogens segregate and stack parallel into aligned domains. This leads to layers at approximately 10 nm periodicity. Combination of directionality of halogen bonding, mesogen parallel stacking, and minimization of the interfacial curvature translate into an overall alignment in bulk and films up to millimeter scale (Houbenov et al, <i>Nat. Commun.</i>,<b> 2014, 5,</b> 4043). The material can also be classified showing supramolecular halogen-bonded polymeric liquid crystallinity. As many polymers present sites capable of receiving halogen bonding, we suggest generic potential of this strategy for aligning polymer self-assemblies.

Halogen-bonded mesogens direct polymer self-assemblies over millimeter length scale

249th National Meeting (2015)

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